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Funding provided by NOAA Sectoral Applications Research Project. ALTERING CLIMATE. Basic Climatology Oklahoma Climatological Survey. ATMOSPHERIC POLLUTANTS. Acid Rain. Acid Rain is the precipitation that carries higher-than-normal amounts of nitric or sulfuric acid - PowerPoint PPT Presentation


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ALTERING CLIMATEBasic ClimatologyOklahoma Climatological SurveyFunding provided by NOAASectoral Applications Research Project1ATMOSPHERIC POLLUTANTS2Acid RainAcid Rain is the precipitation that carries higher-than-normal amounts of nitric or sulfuric acidActually includes dry deposition; some of these particles may settle out of the atmosphere in the absence of rain Neutral rain is slightly acidic (pH around 5.6) due to naturally-occurring chemicalspH of 7.0 is neutral; less than that is considered acidic, greater than that is alkalineEach 1.0 decrease in the scale indicates a 10-fold from the next-higher number (e.g., water with a pH of 5.0 is 10 times more acidic than one with a pH of 6.0)The most acidic rain in the U.S. (as of 2000 according to the EPA) had a pH of 4.3 Causes of Acid Rain:Volcanic eruptionsDecomposition of organic matterBurning woodBurning fossil fuelsMain anthropogenic (man-made) sources are sulfur dioxide (SO2) and Nitrogen Oxides (NOx) emitted by power plants, industry, and automobiles

Source: NASA3Impacts of Acid RainSurface Waters: Kills or sickens fish and other food sources (such as insects) upon which they relyExcess nitrogen depletes oxygen (eutrophication), causing algae blooms and fish killsLeaches heavy metals, particularly aluminum, from the soil, which is toxic to many fish and plantsAlkaline substances in the soil may counteract the effects of acid rain, but may become overwhelmedMay get a shock with spring snowmelt, runoffForests:Acid buildup in soil weakens trees, making them more susceptible to other threatsDissolves and washes away nutrientsFog at higher elevations constantly bathe trees in acid, washing away nutrientsMaterials: Causes blotches and fading of painted surfaces, including carsDeterioration of stone, particularly marble and limestoneCorrosion of metals such as bronze and steelVisibility:Molecules are larger and scatter more incoming light, reducing visibilityAccounts for 50-70% of visibility reduction in the eastern U.S.Human Health:Increase in heart and lung disorders, including asthma and bronchitisCauses an estimated $50 billion annually in premature mortality, hospital admissions, and emergency room visits4Reducing Acid RainMonitor and ReportReduce smokestack emissionsRemove sulfur at the source; clean coalUse scrubbers to remove SO2 before it leaves the smokestack (chemical interactions that bind it with other substances that can be collected)Use catalytic converters to remove NOx from automobile emissionsUse alternative energy sourcesNatural gas: still pollutes, but not as muchNuclear energyHydropowerRenewable energy: wind, solar, geothermalElectric vehiclesRestore damaged environmentsLimestone may be added to water to cancel out some of the acidity on a short-term basis (but very expensive)5OzoneThe ozone layer is a concentration of ozone (O3) particles in the stratosphereOzone is very good at absorbing harmful high-energy ultraviolet radiation from the sunDuring the 1980s it was discovered that chemicals, called chlorofluorocarbons (CFCs), were depleting the concentration of atmospheric ozoneCFCs were commonly used in refrigeration, aerosol sprays, and solventsOne chlorine atom can break apart more than 100,000 ozone moleculesThe Montreal Protocol agreement in 1987 put in place a ban on CFCsAlternative chemicals and technologies have been developed to replace CFCsAs a result of these actions, the ozone layer is expected to recover by 2050Source: NASA

6But I Thought Ozone Was GoodUp high, ozone filters harmful solar radiationbut its not a good thing to breatheCan worsen bronchitis, asthma, and emphysemaProlonged exposure can irritate and scar lung tissueOzone can also harm vegetation and ecosystems and make trees more susceptible to diseaseOzone is created from Nitrogen Oxides (NOx) the same bad guys as in acid rainUltraviolet radiation from the sun converts NOx near the surface into ozoneStrong sunlight and high temperatures accelerate the processWinds may carry emissions far from their sources, so regions downwind may have similar air quality problems

Source: EPA7Carbon DioxideCarbon Dioxide (CO2) is a critical component of the Earths biosystemsUsed by plants to convert to sugars (energy)Plants release oxygen as a waste product, which animals useAnimals, in turn, release carbon dioxide as a waste productHowever, high in the atmosphere, the radiative properties of CO2 cause troubleRelatively transparent to incoming solar radiation but a good absorber of longer-wavelength radiation emitted by the EarthCO2 essentially allows in the suns energy but traps the outgoing energy from the Earth, causing temperatures to rise in what is known as the Greenhouse EffectCarbon dioxide has been building in the atmosphere as a byproduct of the combustion of fossil fuels coal, oil, and natural gasSome CO2 is a good thing recall that the Earths average temperature would be about 0F without itOther gasses can also add to the greenhouse effect, particularly methane, which is a byproduct of agricultural production

Source: Washington Department of Ecology


10HOW THEY AFFECT CLIMATE11Factors Affecting ClimateOrbital Variations (millennia)Eccentricity the shape of the orbit around the sun (90,000-100,000 years)Obliquity changes in the angle that Earths axis makes with the plane of Earths orbit (40,000 years)Precession the change in the direction of the Earths axis of rotation (25,800 years)

12Factors Affecting ClimateOrbital Variations (millennia)Solar Variations (decades)A fairly regular 9-14 year (average 11) cycle in solar energy output, seen through the number of sunspotsLast solar maximum was in 2001; next is predicted for May 2013

Source: NASA13Factors Affecting ClimateOrbital Variations (millennia)Solar Variations (decades)Oceanic Circulations (decades)Periodic episodes of warming or cooling in different ocean basinsMay combine with other circulation patterns to reinforce or counteract other climate trendsSource: NASA

14Factors Affecting ClimateOrbital Variations (millennia)Solar Variations (decades)Oceanic Circulations (decades)Volcanic Emissions (1-2 years)Sulfate aerosols block solar radiation from surface, causing much lower temperatures (lasts 1-2 years)Only eruptions whose plumes penetrate the lower stratosphere cause large variability; very few volcanoes do soSource: NASA

15Factors Affecting ClimateOrbital Variations (millennia)Solar Variations (decades)Oceanic Circulations (decades)Volcanic Emissions (1-2 years)Change in Land Cover (gradual changes, affecting albedo)Deforestation: more vegetation creates cooler, wetter surface conditions; less vegetation leads to warmer, drier conditionsIce cover: more ice reflects more sunlight, leading to cooling; less ice allows more sunlight to be absorbed, warming the surfaceSource: NASA,USDA

16The recent warming is unusual

17and solar variability cannot explain it


DroughtsWet!Ice StormsOklahomas Winters Have Warmed19Got rid of the blue background. Not the content however. CLIMATE CHANGE PROJECTIONS20International Panel on Climate ChangeIPCC Findings from 2007 Assessment:Higher confidence now exists in projected patterns of warming than exists for other elements such as rainfallHot extremes and heat waves will increaseHeavy precipitation event frequency will continue to increaseSnow cover and sea ice continues to shrinkSea levels will rise, but uncertain as to how much and timingStorm tracks are projected to move polewardIncreasing acidification of the oceanFurther 21st century emissions will contribute to warming & sea level rise for more than a millennium21

Societal response is key

Green ResponseMiddle RoadMaximum GrowthSocietal Response

Temperature Projections: A Range of Possibilities

Annual U.S. precip will increase in the northeast and decrease in the southwest

High ConfidenceOklahoma ProjectionsTemperature (Middle Road scenarios)Warming of 2-4F in annual average temperature by the 2020sWarming of 4-7F in annual average temperature by the 2090sSummer becomes longer and spring weather arrives earlierWinters warm longer frost-free periods and a longer growing seasonEarlier maturation of winter wheat and orchard crops leave them more vulnerable to late freeze eventsPrecipitationRain-free periods will increase, but individual rainfall events will be more intenseIncreased year-round evaporation from the ground and transpiration from green vegetationDrought frequency and severity increasesThe risk of wildfires increases, especially during summer25Oklahomas Water FutureFewer (but more intense) precipitation events:More runoff, more floodingMore pollution from runoffIncreased erosionCrop damageIncreased temperatures will increase evaporationWill dry out more severely between precipitation eventsPossibly less water available, even if yearly totals increase26Winners and LosersThere will be winners and losers from the impacts of climate change, even within a single region, but globally the losses are expected to far outweigh the benefits. from the National Academies report Understanding and Responding to Climate Change.